1. Field of the Invention
The present invention relates to a timing scrambling method and timing control device thereof, and more particularly, to a timing scrambling method and timing control device thereof capable of adjusting a scrambling signal with time.
2. Description of the Prior Art
A liquid crystal display (LCD) is a flat panel display which has the advantages of low radiation, light weight and low power consumption and is widely used in various information technology (IT) products, such as notebook computers, personal digital assistants (PDA), and mobile phones. An active matrix thin film transistor (TFT) LCD is the most commonly used transistor type in LCD families, especially in the large-size LCD family. A driving system installed in the LCD, includes a timing controller, source drivers and gate drivers. The source and gate drivers respectively control data lines and scan lines, which intersect to form a cell matrix. Each intersection is a cell including crystal display molecules and a TFT. In the driving system, the gate drivers are responsible for transmitting scan signals to gates of TFTs to turn on the TFTs on the panel. The source drivers are responsible for converting digital image data, sent by the timing controller, into analog voltage signals and outputting the voltage signals to sources of the TFTs. When the TFT receives the voltage signals, a corresponding liquid crystal molecule has a terminal whose voltage changes to equalize the drain voltage of the TFT, and thereby changes its own twist angle. The rate that light penetrates the liquid crystal molecule is changed accordingly, and thus different colors can be displayed on the panel.
The driving signals of the source drivers are generated by a timing controller. With advancements in LCD panel size, image resolution, and high data rates, high speed transmitting interfaces or more transmitting channels are required for transmitting data between the source drivers and the timing controller. Electric magnetic interruption (EMI) is significantly increased while transmitting considerable data between the source drivers and the timing controller, however. Prior art solutions reduces the electric magnetic interruption by narrowing swings of the signals between the source drivers and the timing controller through the utilization of a spread spectrum clock generator (SSCG), or a scrambling code, wherein the scrambling code is the most common method of reducing the electric magnetic interruption. The concept of reducing the electric magnetic interruption via the scrambling code is to scramble the regularity of data.
Please refer to FIG. 1, which is a schematic diagram of a conventional timing controller 10. The timing controller 10 adopts the scrambling code for decreasing the electronic magnetic interruption in a liquid crystal display. As shown in FIG. 1, the timing controller 10 generates data SD_SD1-SD_SDN for source drivers SD1-SDN by scrambling data D_SD1-D_SDN according to a timing scrambling signal. The timing scrambling signal is generated by a random number generator 100. The source drivers SD1-SDN generate the same timing scrambling signal via the random number generator 100 of each source drivers SD1-SDN, and then acquire the original data D_SD1-D_SDN via decoding the received data SD_SD1-SD_SDN according to the timing scrambling signal. The distribution of the electronic magnetic interruption on the spectrum becomes more dispersive and the peak of the electronic magnetic interruption can therefore be reduced.
Since the timing controller 10 only uses the random number generator 100 to generate the timing scrambling signal, however, the data SD_SD1-SD_SDN will have similar patterns when the data D_SD1-D_SDN are fixed. In such a condition, adopting the scrambling code for reducing the electronic magnetic interruption is ineffective.